TPO membrane covers domed roof of storm shelter in Mo. city

A storm shelter at the Webb City High School in Webb City, Mo., uses a weather-resistant "thermoplastic polyolefin" membrane, according to this article. The inflated dome will be sprayed with insulation on its underside, and then rebar and "shotcrete" will be added. Once built, the storm shelter is expected to resist an EF-5 tornado and accommodate 3,000 people.